Describing differences between databases

We study the novel problem of efficiently computing the update distance for a pair of relational databases. In analogy to the edit distance of strings, we define the update distance of two databases as the minimal number of set-oriented insert, delete and modification operations necessary to transform one database into the other. We show how this distance can be computed by traversing a search space of database instances connected by update operations. This insight leads to a family of algorithms that compute the update distance or approximations of it. In our experiments we observed that a simple heuristic performs surprisingly well in most considered cases. Our motivation for studying distance measures for databases stems from the field of scientific databases. There, replicas of a single database are often maintained at different sites, which typically leads to (accidental or planned) divergence of their content. To re-create a consistent view, these differences must be resolved. S...

• Type: Conference
• Year: 2006
• Where: CIKM
• Authors: Heiko Müller, Johann Christoph Freytag, Ulf Leser
• Keywords: CIKM 2006, Database, Information Management, Update Distance, Update Operations